What does the NLEVEL option in PROC FREQ provide?

The NLEVEL option in PROC FREQ is specifically designed to provide the number of distinct levels or unique values for the specified categorical variables in a dataset. When this option is utilized, it provides insight into the diversity of the data by counting how many unique categories or classes exist for each variable. This information is particularly useful in understanding the structure of categorical data, identifying potential issues with sparse categories, and determining the richness of the data.

Other options can relate to the general functionality of PROC FREQ but do not accurately describe what NLEVEL does. For example, while the maximum frequencies of variables and overall counts of variables might seem relevant in frequency analysis, they do not reflect the distinct value count offered by NLEVEL. Similarly, standard deviations pertain to numerical data analysis and do not apply to categorical data analyzed through PROC FREQ in the context of this specific option. Thus, using the NLEVEL option is advantageous for quantifying the unique levels of the categorical data being examined.